Assessing the levels of pesticide residues in livestock products and water around Lake Mburo National Park, South Western Uganda.

Abstract:

An assessment on the levels of pesticide residues in livestock products and water around Lake Mburo National Park, South Western Uganda was carried out in the year 2010/2011. This study was necessary in view of the fact that there is inadequate data on the levels of pesticide residues in live stock products and water despite the increasing use of pesticides to control animal disease vectors specially ticks. A structured questionnaire was used to interview the farmers on the types of pesticides used to control animal disease vectors, and their practices, knowledge and attitudes on the use of pesticides. A total of sixty (60) farmers were interviewed and data analysed using Statistical Package for Social Sciences (SPPSS 19). Samples of milk, muscle and water were also collected and analyzed in a laboratory for organochlorine, organophosphate and pyrethroid residues.
From the study, 100% of the farmers controlled animal disease vectors by use of pesticides. The survey revealed a total of ten (10) different pesticides that were being used by the farmers in the study area with synthetic pyrethroids (33.6%) being widely used followed by organophosphates and formamidine (22.1%). There was no organochlorine pesticide being used by the farmers and no organochlorine pesticide residues were detected. However, chlorfenvinphos residues of 0.13 mg/l, 0.11 mg/l, were detected in water sample 1 and 2 from Kanyarweru subcounty while 0.17 mg/l, 0.12 mg/l, 0.41 mg/l, 0.12 mg/l of chlorfenvinphos residues were detected in water sample 1, 2, 3 and 4 from Nyakashara subcounty. In addition, chlorfenvinphos residues of 0.32 mg/l, were detected in milk sample 5 from Sanga Subcounty while 0.28 mg/l and 0.31 mg/l were detected in milk sample 2 and 5 from Nyakashashara subcounty. Also, unquantifiable levels of chlorpyrifos residues, an organophosphate were detected in meat samples 1, 2 and 4 from Nyakasharara Sub County. No pyrethroid residues were detected in the animal products and water samples analyzed.
The presence of pesticide residues in animal products and water could be attributed to the practices, attitudes and knowledge about the use of pesticides. The study revealed that
viii
78% of the farmers disposed their pesticide containers around the spray area. It was also revealed that most of the spray areas were located in the radius of not more than 1km from the water source. This could be the probable cause of water contamination with pesticide residues as a result of runoff. In addition, 88% of the farmers interviewed had no knowledge on the withholding periods of the pesticides.
Despite the fact that some of the pesticide residues detected in the livestock products and water are below the Maximum Residue Levels(MRLs) with increasing pesticide use for tick control in Uganda, there is a possibility of increased pesticide residue levels in livestock products and water above the MRLs. In addition, given that pesticides are toxic compounds their presence in food, even in trace amounts, should be avoided.

Description:

A dissertation submitted to Makerere University, school of Forestry, Department Of Environment Management, College Of Agriculture and Environmental Sciences, in partial fulfilment of the requirements for the award of the Degree Of Master Of Science in Environment and Natural Resources